Menounou, N. Texas A&M University, firstname.lastname@example.org
Presley, B. Texas A&M University, email@example.com
EARLY DIAGENESIS OF MERCURY AND OTHER TRACE METALS IN SEDIMENT CORES FROM CENTRAL TEXAS LAKES
Metals released during fossil fuel use are important atmospheric pollutants. Mercury and other trace metals can be transferred to an aquatic environment through atmospheric deposition. In the work reported here, a number of sediment cores were retrieved from central Texas lakes in the proximity of coal-fired power plants in search of local, anthropogenic effects. Elevated concentrations were present in recently deposited sediments. In a sediment core from one lake there was a ten fold increase in mercury concentration between the bottom (10 ng/g), where the sediment was approximately 100 years old and the surface (100 ng/g). Similar trends were found for other trace elements (Cd, Se, Ni, Cu). Sequential extraction techniques revealed that the trace metals are also affected by early diagenetic processes that are unique for each element. Cd is primarily affected by Mn redox cycling whereas Pb and Ni are primarily affected by Fe redox cycling. Mn shows unique speciation profiles, with almost 50% bound to the exchangeable (loosely adsorbed as on clays) phase and carbonate-related phases.
Day: Thursday, Feb. 4
Location: Sweeney Center